Power fuse apparatus

ABSTRACT

The invention relates to a power fuse assembly including a power fuse device having end ferrules and stab-type electrical contacts extending rearwardly from the end surfaces of the ferrules for electrically engaging stab-jaw connectors without protruding laterally beyond the lateral dimension of the power fuse device. This electrical interconnect design permits compact lateral packaging of a plurality of power fuse assemblies in multiphase electrical systems.

United States Patent Hodgson Feb. 1,1972

[54] POWER FUSE APPARATUS [21] Appl. No.: 30,515

[52] US. Cl ..337/187,337/l6l,337/180,

3,489,978 1/1970 Mikulecky ..337/l6l X 2,892,060 6/1959 Gaskill ..337/l6l FOREIGN PATENTS OR APPLICATIONS 487,423 d/1938 Great Britain ..337/l80 Primary Examiner-Bemard A. Gilheany 1 Assistant ExaminerF. E. Bell AttorneyF. l-l. Henson, C. F. Renz and M. P. Lynch [57] ABSTRACT 337/248, 337/251 [51 nu; c1. ..H0lh 85/02 The te n relates to a Power fuse assembly including a 58 1 Field of Search ..337/187, 188, 208, 209, 213, Power fuse device having end ferrules and yp electrical 3 2 4 2 25 252 2 3 15 186, 5 248 contacts extending rearwardly from the end surfaces of the ferrules for electrically engaging stab-jaw connectors without 56] References Cited protruding laterally beyond the lateral dimension of the power fuse device. This electrical interconnect design permits com- UNITED STATES PATENTS pact lateral packaging of a plurality of power fuse assemblies in multiphase electrical systems. 2,794,098 5/1957 Jacobs ..337/248 X 2,800,556 7/1957 Swain et a1 ..337/248 10 Claims, 6 Drawing Figures BOA 34 U Q l 24T ELL 1 84 L y T A I n 6 g :E: :z: k L z: 36

PATENIED rm H972 3539873 .SHEEI1UF3 Fl G. I.

FIGZ) V WITNESSES INVENTOR Alfred W. Hodgson 01 BYMMPOW ATTORNEY POWER FUSE APPARATUS BACKGROUND OF THE INVENTION The power fuse electrical interconnect mounting techniques generally utilized are not compatible with efficient compact packaging requirements.

The common technique employed to provide electrical connection to the cylindrical end ferrules of a barrel-type fuse utilizes a fuse clip arrangement for clamping the circumferential surface of the end ferrules. The increased lateral dimension of the fuse assembly produced by the clamping jaws of the fuse clip increases the lateral spacing required between adjacent fuse assemblies in high-voltage systems such as line starters of the type disclosed in the copending application of the inventor, Ser. No. 30,409, filed Apr. 21, 1970 and assigned to the assignee of the present invention.

SUMMARY OF THE INVENTION This invention discloses a power fuse assembly design which eliminates requirements for electrically contacting a circumferential surface of the end ferrules of a barrel fuse by providing stab-type electrical contacts which extend rearwardly from flat plates affixed to the flat end surfaces of end ferrules without protruding laterally beyond the diameter of the barrel fuse. This design permits compact lateral packaging of power fuses as well as reducing the overall weight of the fuse assembly.

Additionally, the design provides pivotal engagement and disengagement of the stab-type electrical contacts with stationary stab jaws to facilitate insertion and removal of the power fuse assembly by means of a fuse puller, or hook-stick.

The invention will become more readily apparent in the following exemplary description of a double barrel fuse assembly in connection with the accompanying drawing.

DESCRIPTION OF THE DRAWING FIG. 1 is a rear perspective view of a power fuse incorporating the teachings of this invention,

FIG. 2 is a side perspective view of power fuse assembly including the power fuse of FIG. 1,

FIG. 3 is a perspective I view of the power fuse mounting plate of FIG. 2,

FIG. 4 is a front schematic view of an arrangement of three of the power fuse assemblies of FIG. 2,

FIG. 5 is a partial elevation illustrating the latching and unlatching operation of the power fuse assembly of FIG. 2, and

FIG. 6 is a partial elevation of the apparatus of FIG. 2 illustrating optional auxiliary fuse contacts.

DESCRIPTION OF THE PREFERRED EMBODIMENT Preferring to FIG. 1, there is illustrated a double barrel power fuse apparatus 10 comprised of barrel-type fuse elements 12, top end ferrules l6 and bottom end ferrules l8 electrically conductive end plates 20 and 30 affixed to the flat end surfaces of the ferrules l6 and 18, respectively, and stab-type electrical contacts 22 and 32 extending rearwardly from the end plates 20 and 30. A blown fuse indicator 50 extends through the end plate 20.

While the double barrel power fuse is illustrated, inasmuch as it is widely used in high-voltage line starters, it is understood that the electrical interconnect technique described below is equally applicable to other fuse configurations.

The electrically conductive end plates 20 and 30 are brazed to the flat end surfaces of end ferrules 16 and 18 to form electrically bridging members.

The lateral width dimension W of the end plates is selected to be a value equal to or less than the diameter D of the barreltype fuse elements 12 so as to minimize lateral protrusions which would detract from the compact lateral packaging of the fuse units as illustrated in FIG. 4.

The lateral width dimension W of the end plates illustrated is selected to correspond substantially to the lateral dimension D of the fuse elements 12 while allowing sufficient plate material for brazing to the end plates.

Stab-type electrical contacts 22 and 32 are illustrated as being an integral part of the end plates 20 and 30 respectively. Inasmuch as the electrical connection to the fuse elements 12 is provided by the end plates 20 and 30 through stab-type electricalcontacts 22 and 32, the requirement for jaw-type electrical contacts for engaging the circumferential surface of the end ferrules l6 and 18 is eliminated. The stab-type electrical contacts 22 and 32 extend rearwardly from the end plates 20 and 30 respectively without protruding laterally beyond the lateraldimension W of the end plates 20 and 30 and without extending significantly beyond the length of the fuse devices 12. The leading edge Ll of the stab-type electrical contact 22 is disposed in a general vertical position whereas the leading edge L2 of the stab-type electrical contact 32 is disposed in a generally horizontal position.

Electrical engagement of the stab-type electrical contacts 22 and 32 with stab-jaw connectors 22A and 32A respectively is illustrated in FIG. 2.

The electrical connector 32A is affixed to a mounting member with a connector 34 providing means for electrical connection to electrical bus.

The mounting member 60 is illustrated in FIG. 3. A pair of upwardly protruding interlocking fingers 62 engage slots 64 of the lower end plate 30 as illustrated in FIG. 2. The interlocking fingers 62 serve as pivot points about which the power fuse apparatus 10 as rotated between an electrically disengaged position D and an electrically engaged position E. The interlocking fingers 62 terminate in the form of an arrow head 64 comprising laterally protruding surfaces 64A and 648. The surface 64A limits the forward rotation of the power fuse assembly 10 to the disengaged position D and cooperates with the downwardly protruding leading edge 65 of the mounting member 60 to physically support the power fuse apparatus in position D, thereby eliminating prolonged manual handling of the fuse apparatus. The surface 648 prevents vertical lifting of the fuse apparatus rearward resulting from contact between stab contact 32 and stab jaw connector 32A and thus insures positive mating between the stab contacts 20 and 30 and the stab jaw connectors 22A and 32A.

The mating of stab contacts 22 and 32 with stab jaw connectors 22A and 32A occurs sequentially with the mating of stab contact 22 with stab jaw connector 22A occurring first. This sequential mating minimizes the force required to position the power fuse apparatus in the engaged position E.

The stab contact 32 extends downwardly from the back portion of the end plate 30 in a perpendicular relationship with the end plate 30. The leading edge L2 is aligned to engage the stab jaw connector 32A when the power fuse apparatus is in position E. The tapered opening J of the stab jaw connector 32A compensates for slight misalignment of the stab contact 32.

The lead edge Ll of the stab contact 22, while generally secured in a vertical position, is disposed to define a substantially perpendicular relationship with the arcuate path of travel defined by the rotational motion of the power fuse apparatus 10 about the interlocking fingers 62. The mating stabjaw connector 22A is secured to a mounting member at a similar angular relationship to the arcuate path of travel of the power fuse apparatus so as to electrically engage the stab contact 32 at position E and thus provide electrical continuity between the end plate 20 and a connector 36. Connector 36 provides electrical connection with an electrical bus. The generally vertical engaging relationship of the stab contact 22 and the stab jaw connector 22A compensates for vertical misalignment of the power fuse apparatus 10.

In addition to the support provided by the mounting member 60, a spring loaded latching member having a horizontal opening 80A, is pivotally secured to the mounting member 70 to engage a locking tab 24 extending upwardly from the end plate 20. The latching member 80 functions to compensate for fuse disengaging forces corresponding to electromagnetic forces developed by the typically high current transmitted through the power fuse apparatus. The latching and unlatching of the latch member 80 as well as the pivotal motion of the power fuse apparatus between position D and E is accomplished through an operators use of a fuse puller, or hook-stick device, 90 as illustrated in FIGS. 2 and 5. A pin 92 of the fuse puller 90 is pivotally inserted in an aperture 24A of the locking tab 24 to support the application of a force to the fuse apparatus 10 by an operator for rotating the fuse apparatus 10 between positions D and E. The hook 94 of the fuse puller 90 is inserted in the opening 80A of the latching member 80 and engages the leading edge 84. The fuse puller is pivoted vertically about pin 92 to vertically control the position of the latching member 80 between the latch position L and the unlatched position U. The downward vertical travel of the latching member 80 is limited by pin 86.

Optional thin, lightweight auxiliary contact fingers 98 for engaging the circumferential surface of the end ferrule 16 may be employed, as illustrated in FIG. 6, to improve the transfer of heat from the fuse elements 12 to the mounting member 70 and thus increase the continuous current rating of the power fuse apparatus. Also illustrated in FIG. 6 is a means for limiting the rearward rotation of the fuse apparatus 10 to position E comprising 'Shoulder surface S of end plate 20 which contacts the mounting member 70 to prevent additional rearward rotation of the fuse assembly 10.

lclaim:

l. A power fuse apparatus comprising, a fuse device having oppositely disposed first and second ends, a first and a second ferrule affixed to said first and second ends respectively, a first electrically conductive plate means affixed to said first ferrule and including a first rearwardly extending electrical stab contact disposed in a first plane, and a second electrically conductive plate means affixed to said second ferrule and including a second rearwardly extending electrical stab contact disposed in a second plane which is substantially perpendicular to said first plane.

2. The apparatus of claim 1 wherein said first and second electrically conductive plate means are substantially confined within the diameter dimension of said barrel-type power fuse device and said first and second rearwardly extending electrical stab contacts are confined substantially within the length dimension of said barrel-type power fuse device.

.3. In an electrical power apparatus, the combination of, a power fuse apparatus comprising,

at least one barrel-type fuse device,

a first and second ferrule affixed to either end of said barreltype fuse device,

a first electrically conductive end plate means affixed to said first ferrule and including a first rearwardly extending electrical stab contact disposed in a first plane which longitudinally intersects said fuse device,

a second electrically conductive end plate means being affixed to said second ferrule and including a second rearwardly extending electrical stab contact disposed in a second plane which is perpendicular to said first plane,

said first and second electrically conductive end plate means being substantially confined within the diameter dimension of said barrel-type fuse device,

a first and second electrical terminal means aligned for electrically engaging said first and second electrical stab contacts respectively.

and mounting means for pivotally engaging said second electrically conductive end plate to support vertical rotative motion of said power fuse apparatus to provide forward movement of said power fuse, assembly to establish firstly electrical engagement between said second electri cal stab contact and said second electrical terminal means and secondly electrical engagement between said first electrical stab contact and said first electrical terminal means and backward motion of said power fuse assembly to firstly disengage said first electrical stab contact from said first electrical terminal means and secondly disengaging said second electrical stab contact from said second electrical terminal means, respectively.

4. An apparatus as claimed in claim 3 wherein said second electrical contact extends downwardly from said second electrically conductive end plate means and is substantially perpendicular to said second electrically conductive end plate means with the leading edge of said second electrical contact being substantially horizontal.

5. An apparatus as claimed in claim 3 wherein said first electrical stab contact extends downwardly and rearwardly fromsaid first electrically conductive end plate means, the leading edge of said first electrical stab contact being substantially perpendicular to the arcuate path defined by the rotative motion of said power fuse apparatus.

6. An apparatus as claimed in claim 3 wherein said mounting means includes structure for supporting said power fuse assembly in a forwardly tilted, electrically disengaged rest position.

7. An apparatus as claimed in claim 3 wherein said first electrically conductive end plate means includes an upwardly protruding member, and a spring loaded hook-stick actuated latching arm for engaging said protruding member to maintain said power fuse assembly in a vertical, electrically engaged position.

8. An apparatus as claimed in claim 3 wherein said power fuse apparatus comprises a double-barrel power fuse arrangement with said first and second electrically conductive end plate means functioning as electrical bridge members across the end surfaces of the adjacent barrel-type power fuse devices.

9. An apparatus as claimed in claim 3 including means for contacting said power fuse device to conduct heat therefrom.

10. In an electrical power apparatus as claimed in claim 3 wherein said second electrically conductive end plate means includes passages therein and said mounting means includes upwardly extending pivot arms for operatively cooperating with said passages to support the pivoted engagement between said mounting means and said second electrically conductive end plate means. 

1. A power fuse apparatus comprising, a fuse device having oppositely disposed first and second ends, a first and a second ferrule affixed to said first and second ends respectively, a first electrically conductive plate means affixed to said first ferrule and including a first rearwardly extending electrical stab contact disposed in a first plane, and a second electrically conductive plate means affixed to said second ferrule and including a second rearwardly extending electrical stab contact disposed in a second plane which is substantially perpendicular to said first plane.
 2. The apparatus of claim 1 wherein said first and second electrically conductive plate means are substantially confined within the diameter dimension of said barrel-type power fuse device and said first and second rearwardly extending electrical stab contacts are confined substantially within the length dimension of said barrel-type power fuse device.
 3. In an electrical power apparatus, the combination of, a power fuse apparatus comprising, at least one barrel-type fuse device, a first and second ferrule affixed to either end of said barrel-type fuse device, a first electrically conductive end plate means affixed to said first ferrule and including a first rearwardly extending electrical stab contact disposed in a first plane which longitudinally intersects said fusE device, a second electrically conductive end plate means being affixed to said second ferrule and including a second rearwardly extending electrical stab contact disposed in a second plane which is perpendicular to said first plane, said first and second electrically conductive end plate means being substantially confined within the diameter dimension of said barrel-type fuse device, a first and second electrical terminal means aligned for electrically engaging said first and second electrical stab contacts respectively. and mounting means for pivotally engaging said second electrically conductive end plate to support vertical rotative motion of said power fuse apparatus to provide forward movement of said power fuse, assembly to establish firstly electrical engagement between said second electrical stab contact and said second electrical terminal means and secondly electrical engagement between said first electrical stab contact and said first electrical terminal means and backward motion of said power fuse assembly to firstly disengage said first electrical stab contact from said first electrical terminal means and secondly disengaging said second electrical stab contact from said second electrical terminal means, respectively.
 4. An apparatus as claimed in claim 3 wherein said second electrical contact extends downwardly from said second electrically conductive end plate means and is substantially perpendicular to said second electrically conductive end plate means with the leading edge of said second electrical contact being substantially horizontal.
 5. An apparatus as claimed in claim 3 wherein said first electrical stab contact extends downwardly and rearwardly from said first electrically conductive end plate means, the leading edge of said first electrical stab contact being substantially perpendicular to the arcuate path defined by the rotative motion of said power fuse apparatus.
 6. An apparatus as claimed in claim 3 wherein said mounting means includes structure for supporting said power fuse assembly in a forwardly tilted, electrically disengaged rest position.
 7. An apparatus as claimed in claim 3 wherein said first electrically conductive end plate means includes an upwardly protruding member, and a spring loaded hook-stick actuated latching arm for engaging said protruding member to maintain said power fuse assembly in a vertical, electrically engaged position.
 8. An apparatus as claimed in claim 3 wherein said power fuse apparatus comprises a double-barrel power fuse arrangement with said first and second electrically conductive end plate means functioning as electrical bridge members across the end surfaces of the adjacent barrel-type power fuse devices.
 9. An apparatus as claimed in claim 3 including means for contacting said power fuse device to conduct heat therefrom.
 10. In an electrical power apparatus as claimed in claim 3 wherein said second electrically conductive end plate means includes passages therein and said mounting means includes upwardly extending pivot arms for operatively cooperating with said passages to support the pivoted engagement between said mounting means and said second electrically conductive end plate means. 